Zcash's NU7 upgrade went live on mainnet on Friday. It shortens the target block time to 25 seconds, starts a mechanism that recycles 60% of transaction fees into future miner rewards, and freezes the old Sprout pool. Governance fights over the dev fund follow.
NU7 goes live at block 3,543,405
Zcash's NU7 network upgrade activated on mainnet early Friday at block 3,543,405. Cointelegraph, citing the blockchain tracker ZecStats, put the activation at 02:34 UTC. The project's official account confirmed NU7's activation, Decrypt reported.
Decrypt framed the release around the Network Sustainability Mechanism (NSM), which aims to support the cost of securing the network while mining subsidies decline. The Block and CoinDesk also reported the activation. Both highlighted the shorter block time and the way the upgrade treats transaction fees.
How the Network Sustainability Mechanism recycles fees
The NSM addresses a problem Zcash shares with Bitcoin. Block subsidies fall with each halving, so miners may eventually depend mostly on transaction fees. It is an open question whether fees alone will be enough to keep mining, and therefore security, adequately funded.
Under the NSM, 60% of transaction fees are taken out of circulation. Those coins are later paid out again slowly as part of future block rewards. Decrypt reported that reissuance begins in 2031, with the funds distributed along a gradual curve layered over the existing halving schedule. Cointelegraph gave the start as around February 2031.
The design leaves Zcash's 21 million ZEC supply cap in place. In effect, the mechanism shifts when part of the fee revenue is paid out and does not add to the maximum supply.
Key figures from the upgrade
The reported numbers vary slightly between outlets, mainly on the value of the Sprout balance.
- Activation block: 3,543,405.
- Target block time: cut from 75 seconds to 25 seconds.
- Transaction fees removed from circulation for later reissuance: 60%.
- Start of reissuance: 2031, or around February 2031 according to Cointelegraph.
- Sprout pool balance: about 12,224 ZEC, which Cointelegraph valued at about $15 million and Decrypt at about $16 million.
- Proposed treasury contribution to the NSM: 50,000 ZEC from Zcash Community Grants, still under consideration.
Faster blocks come with an orphan-block trade-off
Cutting the target interval to a third of its old length speeds up confirmations. It also raises the chance of orphan blocks. These are blocks that are valid but get dropped by the network because a competing miner's block spread to other nodes sooner. Cointelegraph noted that actual intervals will drift toward the new target as mining difficulty adjusts.
Decrypt reported on a stress test run by developers of Zakura. The setup involved 80 nodes located in 11 regions, and each block was filled with private transactions. In that test the orphan rate reached 3.43% with 25-second blocks, compared with 1.57% at 75 seconds. The developers expect the live rate to stay under 1%, because real mining is more concentrated and blocks are far emptier than in the test.
NU7 also caps how much private transaction activity fits in each block. According to the upgrade specification cited by Decrypt, the cap lowers the amount of data wallets need to go through to locate incoming payments. Cointelegraph described the same limits as aimed at easing wallet synchronization.
The Sprout pool is frozen, not burned
NU7 retires Sprout, Zcash's original privacy pool from 2016. Under Zcash Improvement Proposal (ZIP) 2003, the upgrade rejects version 4 transactions, the only format that can spend Sprout funds. Cointelegraph reported that the remaining coins cannot be transferred once the new rules apply, although they remain in existence.
The specification leaves room for a later upgrade to bring back access, whether by turning version 4 transactions back on or through some other retrieval method. Cointelegraph reported that the specification cautions that spending access might not return. The outlets do not report any concrete recovery plan.
Where the outlets agree and where they differ
All four outlets agree on the core facts: the mainnet activation, the 25-second target and the 60% fee treatment. The Block and CoinDesk were available only as headlines and summaries. Their reporting supports the activation and these headline features, and nothing more.
The fuller accounts add different pieces. Decrypt covers the governance background, the orphan-rate test and the NSM's history. Cointelegraph concentrates on the Sprout pool and the technical specification. The outlets differ on the value of the frozen balance, at about $16 million versus about $15 million. They also differ slightly on the start of reissuance, which Decrypt gives as 2031 and Cointelegraph as around February 2031. The two figures are compatible, but only Cointelegraph names a month.
Governance debate follows the upgrade
According to Decrypt, the NSM was the first project of Shielded Labs and builds on an earlier idea from developer Nate Wilcox, originally called the Zcash Posterity Fund. Shielded Labs' first design would have replaced halvings with a smooth issuance curve. Community panels backed it, but coinholders did not, so an alternative that keeps halvings was built instead.
Jason McGee of Shielded Labs wrote that the original design was "simpler and better" but that he respected the process. He added that changing the protocol "should be difficult."
They said "tensions were high" and set an expedited schedule.
What to watch next
Proposals are due by November 8. Polls of coinholders and community panels run from November 16 to November 30. If rough consensus emerges, the groups say they will support a further upgrade, NU 7.1, to implement it.
Other open questions remain. One is whether the live orphan rate stays under the 1% that Zakura's developers expect. Another is whether the proposed 50,000 ZEC treasury contribution to the NSM advances. A third is whether any future upgrade addresses the frozen Sprout balance.
Market snapshot
| Asset | Price | 24h | 7d | Market cap |
|---|---|---|---|---|
| Bitcoin (BTC) | $75,935 | -5.4% | -2.0% | $1.53 trillion |
CoinGecko data as of 2026-11-06 (UTC).
FAQ
What does Zcash's NU7 upgrade change?
NU7 cuts the target block time from 75 seconds to 25 and activates the Network Sustainability Mechanism. It also limits shielded activity per block to ease wallet scanning and retires the Sprout pool. The 21 million ZEC supply cap and the halving schedule stay in place.
What happens to the 60% of fees the NSM removes?
The coins are withdrawn from circulation and later released again over time via future block rewards. Decrypt reported that reissuance begins in 2031, and Cointelegraph said around February 2031. The supply cap of 21 million ZEC is preserved.
Can funds in the Sprout pool still be spent?
Not under the current rules, because NU7 rejects the version 4 transactions needed to spend them. The coins have not been burned, and the specification leaves room for a future upgrade to bring back access. It also warns that access may never return.
Sources
- Decrypt: Zcash's NU7 Upgrade Goes Live, Recycling 60% of Fees to Fund Future Block Rewards (2026-11-06)
- Cointelegraph: Zcash NU7 upgrade goes live, leaves 12,224 ZEC stranded in Sprout pool (2026-11-06)
- The Block: Zcash’s major network upgrade NU7 goes live on mainnet, cutting block time by threefold (2026-11-06)
- CoinDesk: Zcash’s landmark NU7 upgrade goes live, speeding up private payments (2026-11-06)
- CoinGecko (market data)
Written by the Coinvote news desk from reporting by Decrypt, Cointelegraph, The Block and CoinDesk. Not financial advice.
